When i am entering a value like “” in textbox then its throwing following error.

Someone told me to use Server.HTMLencode/Server.HTMLdcode. but i dont know how to use it with textbox. Please help me.
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
you must pass special caracter in your textbox for example < or > …
you can adjust ValidateRequest to false in order to authorize, you adjust on your page
link : http://www.asp.net/whitepapers/request-validation